1st was something about "submission already existing" which would be impossible because my project is compiled and build very fresh. Then it was something "the file has been deleted" or something. Then there were other errors and the last is:

"ERROR - You're only allowed to upload 2 Portal submissions per day, and it looks like you've already uploaded yours."

It's a bug. You may have to wait a week until the programmer responsible for fixing it gets back from vacation. You aren't the only one having the problem, if you haven't noticed any of the other threads.